The boss of Heathrow yesterday said Chinese and South American airlines were being turned away from routes into London because the world's busiest airport was full to capacity.

Colin Matthews, the chief executive of the airports operator BAA, said: "We have airlines come to us from South America and China to ask to fly to the UK, and we have to respond, 'only if you can find a slot to buy' which they find very difficult.

"That's why slots have traded for £25m. We are at the limit of the number of take-offs and landingsat Heathrow. It is frustrating, and itis urgent."

His comments came as Heathrow's record traffic in 2011 – 87.4 million passengers – helped BAA, which also owns Stansted, Southampton, Glasgow, Edinburgh and Aberdeen airports, to post an underlying profit of £1.1bn, up 17 per cent on a year ago.

Mr Matthews said Heathrow was ready for the Olympics this summer.

About 80 per cent of total Games traffic will travel through the airport, including 137,000 people – 10,000 more than have ever been inside the airport on a single day – on the day after the closing ceremony.